"The consequence of that is we are basically looking now at a future climate that is beyond anything that we've considered seriously," Chris Field, a member of the Intergovernmental Panel on Climate Change, or IPCC, told the American Association for the Advancement of Science meeting in Chicago.

Field said "the actual trajectory of climate change is more serious" than any of the climate predictions in the IPCC's fourth assessment report called "Climate Change 2007."

He said recent climate studies suggested the continued warming of the planet from greenhouse gas emissions could touch off large, destructive wildfires in tropical rain forests and melt permafrost in the Arctic tundra, releasing billions of tons of greenhouse gasses that could raise global temperatures even more.

"There is a real risk that human-caused climate change will accelerate the release of carbon dioxide from forest and tundra ecosystems, which have been storing a lot of carbon for thousands of years," Field, of Stanford University and the Carnegie Institution for Science, said in a statement.